In modern times, fluoride in public water supplies and in toothpaste has been very effective to reduce dental caries. A consequence of this is that people now make fewer visits to the dentist than was common a generation ago. It therefore becomes important for individuals to pay closer attention to the condition of their own teeth and gums. A dental mirror is necessary to enable one to view the back surfaces of ones own teeth and gums.
Ordinary dental mirrors which have long been used to view the back surfaces of teeth and gums include simply a small mirror mounted at an angle at the end of a handle. These do not provide illumination within the mouth, and they get fogged up with the breath of the subject.
There have been attempts in the prior art to solve both the illumination and fogging problems of dental mirrors. U.S. Pat. No. 3,158,935 issued to Rosenthal in 1964 attempted to provide lighting with neon tubing, and to defog the mirror with a wiper mechanism attached to it.
U.S. Pat. No. 1,764,455 issued to Kulik in 1930 is the most relevant prior art that I know of. Kulik discloses a dental mirror including a handle with an enclosure on the end. A mirror on top of the enclosure has a hole through its center. A light bulb is behind the mirror, and some of its light passes through the center hole of the mirror to provide illumination in front of the mirror. Illumination provided by the Kulik device interferes with the user's view of the mirror image because the illumination is said to be intense and it is right in the center of the mirror (and the mirror image, which it is desired to see clearly). Furthermore, the light produced by the Kulik device does not converge in front of the mirror to provide concentrated illumination. Instead, the light necessarily diverges in front of the mirror and does not provide concentrated illumination.
It is an object of this invention to provide a dental mirror with concentrated and unobtrusive illumination of its object space. Another object is to provide such a mirror with provision for defogging.